In the shallowly semi-lunulate gland of the petiole, this species resembles P. decipiens and P. orinocense. F r o m the former it is at once distinguished by the ternate leaves with their densely pubescent non-glaucous lower surface, while from P. orinocense it is separated by the ternate leaves rounded at apex with shorter hairs on the lateral nerves and midrib of the lower side of the blade, and by the shorter and sparser pubescence of the peduncle. It is apparently most closely related to P froesii of Brazil, from which it differs in the semi-lunulate instead of quadrate petiolar gland, longer, subacute leaves with denser pubescence beneath, more numerous lateral nerves more prominently elevated beneath, and by the pluricostate villosulous peduncle.